newsletter

How do clocks work?

Clocks and watches are both devices which we use for telling time! Since we divide days days into hours, minutes, and seconds, the job of a watch or a clock is to keep track of how many of them have gone by, which is how the clock or watch tells you what the time is!

It’s easy to see that there are lots of different kinds of clocks and watches. For example, some have a face with moving hands that point to numbers and show the time, while others have digital displays that read the time as consecutive numbers showing hours followed by minutes.

In spite of how different they can look, almost all clocks are made using a few same basics: A device that gives it power, a steady system for measuring time, and a display to show you the time! Today, many clocks and watches use a battery or electric plug for their power. To measure the passage of time, some clocks use a pendulum (like a steadily swinging weight), a moving gear, or a quartz crystal that gives off controlled pulses. As these mechanisms steadily count, the time display inches forward and tells you the hour, minute, and seconds of the day!

Further information

Instead of batteries or electricity, older clocks were often wound up (sometimes every day!) and got power from the tension of a spring!

Exploration

Gears up!Lots of clocks are full of gears. Have you ever seen a set of gears? Gears usually look like a series of circles with teeth that lock into each other -- when one gear turns, it turns the other gears whose teeth are locked into it!

Find out if someone in your family has an old broken watch or clock that you can take apart! Make sure to ask for an old watch and don’t use anything without a grown-up’s permission. Carefully undo the parts one by one, and examine the gears inside! If the clock or watch is small, the gears might be really tiny -- use a magnifying glass to get a closer look.

Do you see the teeth on each gear? How many gears are there in total, and how many lock into each other? Can you find which one turns each hand on the clock? If the parts are big enough, try using the tip of a pencil to push them along and see how they turn!

Are you able to put any of the gears back together again after you take them apart? It might be a little bit like putting together a puzzle!!